# Sample Python/Pygame Programs
# Simpson College Computer Science
# http://programarcadegames.com/
# http://simpson.edu/computer-science/

# Explanation video: http://youtu.be/4W2AqUetBi4

import pygame
import random

# Define some colors
black = (0, 0, 0)
white = (255, 255, 255)
red = (255, 0, 0)
green = (0, 255, 0)
blue = (0, 0, 255)


# This class represents the ball
# It derives from the "Sprite" class in Pygame
class Block(pygame.sprite.Sprite):

    # Constructor. Pass in the color of the block,
    # and its x and y position
    def __init__(self, color, width, height):
        # Call the parent class (Sprite) constructor
        pygame.sprite.Sprite.__init__(self)

        # Create an image of the block, and fill it with a color.
        # This could also be an image loaded from the disk.
        self.image = pygame.Surface([width, height])
        self.image.fill(color)

        # Fetch the rectangle object that has the dimensions of the image
        # image.
        # Update the position of this object by setting the values
        # of rect.x and rect.y
        self.rect = self.image.get_rect()


class Player(pygame.sprite.Sprite):
    change_x = 0
    change_y = 0

    def __init__(self, x, y):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.Surface([15, 15])
        self.image.fill(blue)

        self.rect = self.image.get_rect()
        self.rect.x = x
        self.rect.y = y

    def changespeed(self, x, y):
        self.change_x += x
        self.change_y += y

    def update(self):
        self.rect.x += self.change_x
        self.rect.y += self.change_y

        if self.rect.x > 700:
            self.rect.x = 0
        if self.rect.x < 0:
            self.rect.x = 700
        if self.rect.y > 500:
            self.rect.y = 0
        if self.rect.y < 0:
            self.rect.y = 500


# Initialize Pygame
pygame.init()

# Set the height and width of the screen
screen_width = 700
screen_height = 400
screen = pygame.display.set_mode([screen_width, screen_height])

# This is a list of 'sprites.' Each block in the program is
# added to this list. The list is managed by a class called 'Group.'
good_list = pygame.sprite.Group()
bad_list = pygame.sprite.Group()

# This is a list of every sprite. All blocks and the player block as well.
all_sprites_list = pygame.sprite.Group()

for i in range(50):
    # This represents a block
    block = Block(green, 20, 15)

    # Set a random location for the block
    block.rect.x = random.randrange(screen_width)
    block.rect.y = random.randrange(screen_height)

    # Add the block to the list of objects
    good_list.add(block)
    all_sprites_list.add(block)

for i in range(50):
    # This represents a block
    block = Block(red, 20, 15)

    # Set a random location for the block
    block.rect.x = random.randrange(screen_width)
    block.rect.y = random.randrange(screen_height)

    # Add the block to the list of objects
    bad_list.add(block)
    all_sprites_list.add(block)

# Create a red player block
player = Player(20, 15)
all_sprites_list.add(player)

# Loop until the user clicks the close button.
done = False

# Used to manage how fast the screen updates
clock = pygame.time.Clock()

score = 0

# -------- Main Program Loop -----------
while done == False:
    for event in pygame.event.get():  # User did something
        if event.type == pygame.QUIT:  # If user clicked close
            done = True  # Flag that we are done so we exit this loop

        # Set the speed based on the key pressed
        elif event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT:
                player.changespeed(-3, 0)
            elif event.key == pygame.K_RIGHT:
                player.changespeed(3, 0)
            elif event.key == pygame.K_UP:
                player.changespeed(0, -3)
            elif event.key == pygame.K_DOWN:
                player.changespeed(0, 3)

        # Reset speed when key goes up
        elif event.type == pygame.KEYUP:
            if event.key == pygame.K_LEFT:
                player.changespeed(3, 0)
            elif event.key == pygame.K_RIGHT:
                player.changespeed(-3, 0)
            elif event.key == pygame.K_UP:
                player.changespeed(0, 3)
            elif event.key == pygame.K_DOWN:
                player.changespeed(0, -3)

    player.update()
    # Clear the screen
    screen.fill(white)

    # See if the player block has collided with anything.
    blocks_good_list = pygame.sprite.spritecollide(player, good_list, True)
    blocks_bad_list = pygame.sprite.spritecollide(player, bad_list, True)

    # Check the list of collisions.
    for block in blocks_good_list:
        score += 1

    for block in blocks_bad_list:
        score += -1

    font = pygame.font.Font(None, 25)
    text = font.render("The score is " + str(score), True, black)
    screen.blit(text, [5, 5])

    # Draw all the spites
    all_sprites_list.draw(screen)

    # Limit to 20 frames per second
    clock.tick(60)

    # Go ahead and update the screen with what we've drawn.
    pygame.display.flip()

pygame.quit()